Field of the Invention
The present invention generally relates to the use of paraloid impact modifiers for improved durability of golf balls.
Description of the Related Art
Impact Modifiers are key additives for increasing flexibility and impact strength to meet physical properties of composite materials. Impact modifiers compensate for inherent brittleness, or embrittlement occurring at low temperatures, notch sensitivity and crack propagation.
In the design of a golf ball having a dual core with both layers consisting of a polybutadiene rubber composition, a softer inner core covered by a firmer compression outer core can exhibit poor crack durability when impacted at high speeds. Additionally, a ball having a very soft, low compression single piece polybutadiene core can exhibit poor durability properties also.
Impact property modification of thermoplastic polymers by a variety of rubbers, elastomers, and rubbers combined with the thermoplastics has been known for many years. Extensive interest has been shown for at least 30 years in rubbers combined with thermoplastics in a core-shell structure, typically prepared by emulsion polymerization, as exemplified by such commercial combinations as acrylonitrile-butadiene-styrene polymer (ABS) or methyl methacrylate-butadiene-styrene polymer (MBS) impact-property modifiers for poly(vinyl chloride), acrylic/methacrylic core-shell modifiers for polycarbonate, and the like.
The prior art fails to even recognize this problem.